The present application is directed to novel blockers of ultraviolet radiation formed by Perkin condensation of aromatic aldehyes with alpha-aryl acetic acids, followed by esterification with an alcohol.
Ultraviolet-blocking agents may be either inorganic or organic compounds. Inorganic UV blocking agents are effective by virtue of their reflective properties, while organic blocking agents absorb UV radiation and convert it to other forms of energy, mostly heat. Many organic compounds have been prepared and used as ingredients for sunscreening products. Compounds used for this purpose must be stable, nontoxic, and amenable to formulation.
The UV radiation permeating the earth""s atmosphere has wavelengths ranging from about 290 nm to 400 nm. The radiation with wavelengths ranging from 290 to 320 nm is designated UVB radiation and is commonly referred to as the xe2x80x9cburning rays.xe2x80x9d The radiation with wavelengths ranging from 320 to 400 nm is designated UVA radiation and is commonly referred to as the xe2x80x9ctanning rays.xe2x80x9d Overdoses of either kind can cause inflammation, suppress the immune system, and damage DNA.
Compounds of the formula I: 
wherein R is H, linear or branched alkyl of 1 to 20 carbon atoms or aryl of5 to 20 carbon atoms; Z, X and Y are independently H, acylamino of 1 to 20 carbon atoms; acyloxy of 1 to 20 carbon atoms; alkoxycarbonyl of 2 to 20 carbon atoms; amino; linear or branched alkyl of 1 to 20 carbon atoms; linear or branched alkoxy of 1 to 20 carbon atoms; hydroxy; alkylamino of 1 to 20 carbon atoms; dialkylamino of 2 to 40 carbon atoms; arylamino of 5 to 20 carbon atoms; alkylaryl of 6 to 40 carbon atoms; diarylamino of 10 to 40 carbon atoms; halo, carboxyl, or cyano; n is an integer from 1 to 4, and Z can also be 
wherein Rxe2x80x2 is independently selected from the same groups defining R; and Xxe2x80x2 is independently selected from the same groups defining X;
possess a UV useful absorption spectrum with xcexmax which make them suitable as UV blockers.
A preferred class of compounds includes those in which R is linear or branched alkyl; X is hydroxy; Z and Y are independently H or linear or branched alkoxy. In this class, the compounds wherein X is hydroxy; Y is H, n=2 and Z is alkoxy; and wherein X is hydroxy; Yn is alkoxy, n=2, and Z is H are particularly preferred.
In the class of compounds where in Z is 
the compounds wherein Rxe2x80x2 and R are independently linear or branched alkyl; Yn is hydrogen, n=2; and Xxe2x80x2 and X are hydroxy, are preferred. The indication of  means that the carbon-carbon double bond configuration may be E or Z.